The current evolvement of third generation long term evolution (3GPP LTE) takes into account the increase of different types of wireless communication devices. In particular besides cell phones machine type communication (MTC) devices are getting more and more widespread. Further such evolvements have to consider that many MTC-devices have less computational power, which could even prevent them to operate in the LTE networks over the complete addressed bands.
For handling such low-cost devices it is therefore envisaged that other resource region are embedded in the normal LTE resource blocks, in particular supporting other modulation schemes. Known is in particular the narrowband-IoT (NB-IoT) modulation, which is dedicated for low-cost and low-bandwidth devices particularly used for Internet of Things (IoT) applications, as well as LTE-category 0 or 1.
Further some of the MTC devices are operating in areas with bad coverage, which cannot be fully mitigated by an increased transmission power. This in particular affects metering devices or vending machines. For solving this issue the concept of coverage enhancement resp. enhanced coverage (EC) was developed. This concept includes that by repeatedly transmission of signals an accumulation of energy at the receiving device is carried out which shall result in an increased link budget by e.g. up to 10 dB.
As part of the NB-IoT concept it is foreseen for such wireless communication devices a special set of system information. This special set is submitted in special system information blocks (SIBs), dedicated for narrowband-IoT supporting devices, both in normal and in enhanced coverage. Typically such SIBs are called SIBx-NB, for distinguishing from common SIBs for common devices. For simplicity reasons in the following these SIB for special wireless communication device deployment especially intended for NB-IoT are just called SIBs.
For accessing these SIBs in enhanced coverage they need to be transmitted and correspondingly received in a repeated manner leading to the coverage enhancement gain by combining each repetition.
An issue occurs however when in the periodicity of the SIB transmission the used resource is needed for other purposes. This would harm the SIB transmission as a wrong transport block in the averaging/accumulation process would ruin the whole acquisition/decoding attempt.
This appears in particular, when in parallel in the used frequency band a wideband communication session in the downlink, like multimedia broadcasting to a common mobile handset, is carried out. To acquire the system information all corresponding system information blocks need to be received and combined repeated times depending on their size and the coverage enhancement level needed. It is possible to schedule one or even more than one SIB around those subframes used for other purposes but not all of them without having severe constraints in scheduling. In this case system information blocks are not submitted in each subframe respectively in each subframe intended according to their individual repetition, but only in those where no multimedia broadcasting is scheduled.
The receiving wireless communication devices are put in the position to successfully include into the combining the relevant subframes by additional datafields submitted in one of the system information blocks. These additional datafields, the so-called valid subframe indications, are supposed to indicate in which subframe further SIBs can be expected and which subframes are not to be considered for the accumulation for any of the SIBs because of a wideband communication session, like MBMS or different content.
This situation in particular affects NB-IoT SIBs, all the more when transmitting in enhanced coverage. It is not only disadvantageous as it takes longer and is more power consuming through the subframes with no SIBs. Moreover the SIB1 carrying the valid subframe indications is increased in size through such additional datafields.
It is therefore the goal of present invention to overcome the mentioned disadvantages and to propose a solution for an improved system information block transmission for the dedicated resource region.
Further alternative and advantageous solutions would, accordingly, be desirable in the art.